HTS code 9902.13.22 covers "Modacrylic staple fibers, not carded, combed or otherwise processed for spinning, containing over 35 percent and less than 85 percent by weight of acrylonitrile, 3.9 decitex (plus or minus 2 percent), natural in color, with fiber length between 38 mm and 120 mm (provided for in subheading 5503.30.00)" under the US Harmonized Tariff Schedule. This is the official duty rate charged by US Customs when this product is imported into the United States, sourced directly from the U.S. International Trade Commission and refreshed daily.